So I have a 2012 L99. Yesterday I had headers and ud pulley installed. My car already had cai, Bo White tb, muffler delete and sct tune. I retuned the car for headers and turned the rear o2.s off till I can get a real tune. The headers are tsp w hiflow cats. Since I have no mufflers I left the factory resonator for now. Most would say the car sounds awesome. Its a little loud for my tastes. THe problem is it seems like it had more power before the header install. My thinking is either i lost so much low end torque with the header install or the it needs a proper tune asap. Im also rethinking the muffler delete.

A muffler delete with long tube headers can be excessive. You might want to get a muffler on there. Hit us up for some deals on exhaust options. You shouldn't have any power loss though. If you have any means of scanning the vehicle I would to see if you have any knock.

I guess I will get a mail order tune for now. I talked to the closest dyno timers to me and business is good. They are all booked for a couple of weeks. I talked to the local exhaust shop and he also told me that these cars need back pressure. I’m guessing the tune accounts for that.

So I have a 2012 L99. Yesterday I had headers and ud pulley installed. My car already had cai, Bo White tb, muffler delete and sct tune. I retuned the car for headers and turned the rear o2.s off till I can get a real tune. The headers are tsp w hiflow cats. Since I have no mufflers I left the factory resonator for now. Most would say the car sounds awesome. Its a little loud for my tastes. THe problem is it seems like it had more power before the header install. My thinking is either i lost so much low end torque with the header install or the it needs a proper tune asap. Im also rethinking the muffler delete.

Also, make sure the exhaust isn't touching the car anywhere. If it is it can cause false knock and pull timing thus loss of power.